Sodium crystallises in a bcc unit cell. Calculate the approximate number of unit cells in 9.2 g of sodium ? `"[Atomic Mass of Na = 23 u]"`

Explanation

No. of moles of sodium `=("Mass of sodium")/("Atomic mass of sodium")`
`=(9.2)/(23)=0.4`
One mole of sodium metal contains `=6.022xx10^(23)" atoms"`
0.4 mole of sodium metal contains `=0.4xx6.022xx10^(23)" atoms "=2.4088xx10^(23)" atoms"`
One bcc unit cell contains = 2 atoms
No. of unit cells in 9.2 g of sodium `=(2.4088xx10^(23))/(2)=1.2044xx10^(23)`